Help for plotting 3d sheet-network lattice

Hi, I've recently been trying to plot 3d sheet-network lattices but do so i need to fill the end-caps between two isosurfaces corresponding to different isovalues. What I've been using until now fills the volume inside the subdomains of the isosurface.. Anyone knows how I could achieve this?

t = -0.4;
ti = 0.4;
u = cos(2*g.*x).*sin(g.*y).*cos(g.*z) + cos(g.*x).*cos(2*g.*y).*sin(g.*z) + sin(g.*x).*cos(g.*y).*cos(2*g.*z);
[f,v] = isosurface(x,y,z,u,t);
[f1,v1] = isocaps(x,y,z,u,t);
[fi,vi] = isosurface(x,y,z,u,ti);
[fi1,vi1] = isocaps(x,y,z,u,ti); 
f2=[f;f1+length(v(:,1));fi+length(v(:,1))+length(v1(:,1));fi1+length(v(:,1))+length(v1(:,1))+length(vi(:,1))]; 
v2=[v;v1;vi;vi1];               
col2 = (0:1/(length(f2)-1):1)';
p3=patch('Faces',f2,'Vertices',v2,'FaceVertexCData',col2,'FaceColor','flat','Edgecolor','none'); 

The objective would thus be having only the green parts left on the frontiers of my volume.

Thank you for very much for your help!